Northerners and southerners had developed strongly different relationships to the institution of slavery since the American Revolution and had created political compromises to overcome those differences since the ratification of the U.S. Constitution. The development of the cotton gin for the cheap and quick processing of short-staple cotton revitalized the southern plantation economy after 1793 and drove southern expansion into new cotton lands west of the original thirteen colonies, but it also provided the raw material for the textile mills that emerged in New England in the early nineteenth century. In addition to this alliance of “the lords of the lash and the lords of the loom” (in the words of the Massachusetts senator Charles Sumner) the early western frontiers of North and South also shared a common set of interests in joint trade on the Mississippi and its tributaries. Third, growing inequalities of wealth created divisions among Democrats as well as Whigs in every state in similar ways. Those factors made compromise possible until 1850.